SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7650f6bb91674210df0baec8fab89830bfaf14e266ca8d2d09e671c3fde82a97' 
  AND token = 'UQfcaLKqQcqJx3TMBGhwMZgTvhzpS/vOPBNXcWG/Q7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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