SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e375d71ea270d18d6555a6e3b4e89d08d8632743c667c9544077ecb80fa42ca' 
  AND token = 'g6Pom+jbQ3R/jdKNcoJbYJbZqR3KVyYAvxMDjVxBaNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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