SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df38773c69c16c6947691f4d33b4c2901bc8e5d0321352cac35cc8ef9dae1168' 
  AND token = 'VXOakD2uoxn1UlS6IEqPDHBRZvyvsEc1a56V2wPFrdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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