SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '778d27d120020592d0bf88e2a5e50c872588e2d3fddd1615c3b455daeac9ad32' 
  AND token = 'pvu07axioMYRUKtOrA5Pa3Ty1fkqp+4EHxkG5Bw/Z10=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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