SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbc79d49b1e83f422c2e87d25c1b4bea6e011945ae7b7c493a88a8ffdf816830' 
  AND token = 'OMZ/Vm/4GzEoDfE4aoDVFD6ahSijlEvhlCr7BzPnY5c=' 
  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"
    }
  }
}