SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0e768007c4572bcff21808b3dd0d31602d77ae7d3e721eb94958d76ef0e7df9' 
  AND token = 'E/T5n7bvGKMO3wWGWQiWGLWzz1RRGQiofq7TCunvf9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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