SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '522f6ef081f6056b94922fce825dcc156dd78e97eaa334e0ed30c7361c5d4d83' 
  AND token = 'Pi2iMOWCDCPk7tmw+gyFTSvKblRNMBzfJJXpOGRlLwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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