SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b17ef514624eb49558ef2d0b17f55981bc6b6a86e12284079f28b9e448d5554' 
  AND token = 'l+9Xp9r2YrjnjqFQP2pmxTaxbxgZJAkDnavD9K0MSz4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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