SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ac952176a92820b355d7ed10284a0775d39479ba3c24da79755202e4ef70cd6' 
  AND token = 'Bft22vMv1rEV4reKbmy180F06Oj9FZZYhq2smSlW0Ac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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