SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b079f88d94511ed8737ed1f3b50a0e3cee1c6c6b0bef50acd7417e8d26d300dd' 
  AND token = 'p6rT7GUgWF0yqG0p75Fk9PCxJeU87cglujsCUS/Hg34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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