SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36aa55b8e0362f1f960b08cc3a1fb1dfef3c7fe7a5bbc57548e6f2cddadee9a9' 
  AND token = '+ho0R+2GoTDBO4U0VrYivN6bSaCM5kBsLpBtDWp72nU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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