SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e506e484a14cad738f620a99d084918be93ece0aea4fdc9c43b0fd501f61ef2a' 
  AND token = 'fG6dOqfVhfZMHE42GtgrIW8vmPW+fJRrQKZEQo1DJmM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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