SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c687e4534bb641ea3caabc6defaa0d1d38134fd0d9b0ba9511f0fea55eb06c72' 
  AND token = 'mGwntrtbrU3qurco0SXjjbtrBXGORc1up60QeiqdLS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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