SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '508c6718229b304238cedeb14564342c1bfacb33d2e4fef7bbb8ee7411d46cb6' 
  AND token = 'TLiM/uze8kEFenU0m9ljPIg8D0fbco0kvwSaHMVnLpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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