SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b54027e961e43ab53786d9583ebfc143bf1fad70e53865156da35a8e48109813' 
  AND token = 'R9rF4X/otZ30CYtgMxwXaYmGpIESXys7oSyA+xDINU4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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