SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '300177f28aeb36d9571078e2266ec53f812d6ff97a47d5cd5702ce3525f3bd67' 
  AND token = 'KUrQ1yYo5zv/j/7knXFXP1kwQeNRV6MAWxBrm25HrLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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