SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb6a980b6b7223805eb8a9c11b06717cd84e227f78c27e652b40f23b38fd4049' 
  AND token = 'kSGWV+rQ8mhXzYNGYJaPRLsT1I+jW6W+uGddelMi6do=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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