SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7d221f6bba1512bdf617d394926728e7eeaf77515c20924576e783974b60eb0' 
  AND token = '3xy5koifb8ePxp2WcVrQsoIvg9quWo0LEZvB9LNXjOs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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