SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d2da41ea474af7ea356ce98bafe63d5afd921cffff6cdf1740ab6615f93471d' 
  AND token = 'DbbbgO4+ngNi1WDS7wiw1WbwPYKDXoj5bXcBwhYXRgw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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