SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6707cc632a57a55a5c0522f6b9677ef70d2ef151bac0e363e947c05952c91310' 
  AND token = 'JIJqtS9icmH5SBPBbu3iV7AVYKkAA1cf+AnVqTz4ZvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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