SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39e7d1751e84f5c16015f3e2d00cf519976ddaecbd0f22f22cf7ae1da51d660f' 
  AND token = 'T7NeLMcgkV4WOMgKZKNy4fm9t4EJB8yP9KFw3UGUhiw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}