SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '682f0e90737a728060a036e847f0250cde3005b86b59b5c6b8cdbebff3ebbe17' 
  AND token = 'fFuP/uRJ0PMleAxsXwac4FgJXwhH+P4B2iOXycXYIQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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