SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b02555a7a73b074b7854b3cb1c2307ff0c505d45a076023d4431011f48ab73d6' 
  AND token = 'Lur+EmpFzRqNHMyn2vpQWG/sABMxj9hUfFg9t3/gfxo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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