SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dde7ffc3e2955f2dd436af7d7e296e452f00e40b5163c0e91681b439dc864daa' 
  AND token = 'P4Yth8isZY8yTwmZPUOkI/j+FNTmJDoimfi03uqaq84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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