SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88fd00dfa8a5dd5b2334198277e5586c444f2872451e55e63c61139f4b5e72d6' 
  AND token = 'uHYaw56fdsVuqR8U0DbjeK2AHniMtUS7y3hgASz5bqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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