SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1955ea41d0b3d55a8b80f574b694dec19cc9d134d98699035e0352a58e669511' 
  AND token = '13DSeF8HNVqwe0OLI56rawuJjzEFSGvlNgbKNMfhbRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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