SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab0bb64b0fd869d2463b36c4274a32eb2dea110a783df3f8f3e78e9685066847' 
  AND token = 'fmMI7ktjrmmFNfJylw+Se1BUfRiSBeR5GTFxgcRje98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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