SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2641a1dbbe2ef5959114df97c7018c80cebb3b88683a39dc1c672843307f710b' 
  AND token = 'Bc4LAqzQ1z/Iv1MM5UEnK45FR2gvNPYhTIcuio03kRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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