SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fadf5f269cae077f271415caebfeceb802fb5a2d962e5a46396d9731571276f6' 
  AND token = 'tLVRCginQFO1cc+Yw0qtiB/ZEQ0ceEFCnBVYYCwzT68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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