SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea5103b5a19940d88f78525b6e68c3bd2ba79df06ef2b635e23a4ea740417045' 
  AND token = 'SwDRxZ9sTDPjhUBwbqparHKlDkQ2N8TwZ+l1dcGQevg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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