SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29efb5efa071916d5ae41ef5f0543653ecb56b05a097191e54232efb0483c3af' 
  AND token = 'BehkLeGIz7cu1ssNw16t/Bvd8gEa38EfbcjehWmomPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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