SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '127338e7b9328c615123733bec96b1807b321805fa470f22e5fb9b6727916df2' 
  AND token = 'iIubum2yf/XpXJec/uxLUdYUZjkj1h367UkD5eG1oCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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