SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e811a786bd28e5724ad0ac98641b2da9025f3df7baa0323f127411390ba12b8' 
  AND token = '8EmtPgNm4ve/cf/osAWKtxbwGQIEKVVT9rTR3q4SRiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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