SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b32768d8f30de826c7490374019fb4241f19c2e5da27f11f1d9536c642840677' 
  AND token = 'gnPBU8afbK5jKnPC0OTUE/hmoGSufljRSrCXpSUakvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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