SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8e00faac4a292ceb2da3e3f026705ab16f751486e3cd730527922b8c9f8cd24' 
  AND token = 'eSG2FEVrDuvj09W5b9OEQ1Uhfr6xGd34LOKDytzn2gM=' 
  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"
    }
  }
}