SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ca8c10589a20242dc60b2437f532415686d75fb5c2a052ff93ee3ced27881fa' 
  AND token = 'FcQrP+pwu/eKzVbXea4Sbo8yjAnGD/Dy+XNGZ6CUZL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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