SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19b0fe7acdcae79686877bbc25d626b372c4d2aaceda52a16d573c9d351f360b' 
  AND token = 'T2HbdIj0UQXDXf3oCSoRZHa2qIqvNplIxdGymO8wL1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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