SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70e2dfad31761505b1152115833d8872683e62ce0bd0437af70ba482673595f6' 
  AND token = '0KjgZaLzqUgv2E3q2p7522NqUgfuwlYzV8USvGxRcFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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