SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cb3a0eeb8102f59de4d3e0164da9b81b8c9f5f7dc3732cf0c8601dfdc6b7fc3' 
  AND token = 'gvBVU/hvZ+czJLwCVjMCMFJ2MmcqSV8vHhqilmZvXNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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