SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0b97c70ae21c17604a95dee47cdf8df22f1664affb7ae8699414b8fe4e9da0f' 
  AND token = 'P5Usxid3+ZPs7L2a2AaxHKIHVK///09S1wnxE6Nb4Yc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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