SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fb1e84a2be1d63a8670d56536c37b67eea9030ffcd94d76d4690d616d15d5cb' 
  AND token = 'uJY+SH6s1D/JuVqAPDASRHE+RTkhDjA5HKrbndQXwVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}