SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '814b0d7e949330e892efd5349d38d59a27b4a107f305c0169cd0e315eb88339f' 
  AND token = 'frEMfcshccUc2ofFayIvuNGswNsZS6YkmcnXAGbFf/c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}