SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3f8ca7b43843056dfb23f92b69ac55121cde433d59284d212405eed44349c73' 
  AND token = 'eo1S0cN33PFPGortv+IHPqDktCU5PY7vxWNNkutqJOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}