SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6692c56b1c2b1715f11bcfa58db324a4e12babd06840662be824d35abb4c639a' 
  AND token = 'N86SaqdRSSO3oTnUenYNFV3ZLuUs2HsypbQGKU0SAb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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