SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e237f89302004004589a1da47fd40de359172ab4d8df53b07dd83a39ea41bc11' 
  AND token = 'P7XLE0Y7LseZsKsvwIhRDtUZMjQWvXYtljfLvUcHNX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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