SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6e09f72c0a513b831d4664c7e1080b4f56c06559e6251746725ffc157a3f2d6' 
  AND token = '1zH8FQ8jbpzButS+xP3d2hmsholPV1La+rjJqQVrkzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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