SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c168dfc0b6dbeae5f8091f8cf1582254c84641236035c8f5139917a85eecc26' 
  AND token = 'F+6A7zd4afZDoYtw1q7478RyyqkS1Qa7AYZzPy2nRCE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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