SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27b75b481b1e80f186ef1f69ab920a81901592df7be02061d807dc5d6413d71d' 
  AND token = 'UPqO45qYvXbJKp7IanMqI8ZEvmKyD0eOOeNcgBPsy9s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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