SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f59fe38196fd0967bf4c29f04b745561c49d1363574a0096849c6df97be3c30' 
  AND token = 'K20lYYFqFS6yO7+rcTR8ASScGLzXZCIhcOSXJg/rsHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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