SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89a7757e65bdb1235487929fcb479dd3bf3c8c2a748974b55da47716a127d1b8' 
  AND token = 'XJiCzD1VUX+hBfgMG2zOBX0zzitZPTbtL5qTZ1q7UJU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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