SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3163c7fb06bb49aff4386b3e23c061461be6426abda8ef61676256436085e34a' 
  AND token = 'myYdJ/EnpYpPGFUPSWLVQCjd7Jjb49v8GhVhpVTF9bo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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